pregnant

Let's get into this subject. Is it safe? If so, how? If not, how? Would you?

So I'm facing a little bit of a problem,my sister is a smoker and is a few weeks pregnant,she is trying very hard not to smoke at all but has admitted to having 2 to 3 smokes on some days,so my question is,is it okay for me to suggest vaping as a alternative as long as she doesn't over do it and...